diff --git a/lib/src/http/header.rs b/lib/src/http/header.rs
index 5b380268..de364c3c 100644
--- a/lib/src/http/header.rs
+++ b/lib/src/http/header.rs
@@ -1,9 +1,9 @@
-use std::borrow::Cow;
-use http::hyper::header::Header as HyperHeader;
-use http::hyper::header::HeaderFormat as HyperHeaderFormat;
-use http::hyper::header::HeaderFormatter as HyperHeaderFormatter;
+use std::collections::HashMap;
+use std::borrow::{Borrow, Cow};
 use std::fmt;
 
+use http::hyper::header as hyper;
+
 #[derive(Debug, Clone, Hash, PartialEq, Eq)]
 pub struct Header<'h> {
     pub name: Cow<'h, str>,
@@ -29,9 +29,73 @@ impl<'h> fmt::Display for Header<'h> {
     }
 }
 
-impl<T> From<T> for Header<'static> where T: HyperHeader + HyperHeaderFormat {
+impl<T> From<T> for Header<'static> where T: hyper::Header + hyper::HeaderFormat {
     fn from(hyper_header: T) -> Header<'static> {
-        let formatter = HyperHeaderFormatter(&hyper_header);
+        let formatter = hyper::HeaderFormatter(&hyper_header);
         Header::new(T::header_name(), format!("{}", formatter))
     }
 }
+
+pub struct HeaderMap<'h> {
+    headers: HashMap<Cow<'h, str>, Vec<Cow<'h, str>>>
+}
+
+impl<'h> HeaderMap<'h> {
+    #[inline(always)]
+    pub fn new() -> HeaderMap<'h> {
+        HeaderMap { headers: HashMap::new() }
+    }
+
+    #[inline(always)]
+    pub fn get<'a>(&'a self, name: &str) -> impl Iterator<Item=&'a str> {
+        self.headers.get(name).into_iter().flat_map(|values| {
+            values.iter().map(|val| val.borrow())
+        })
+    }
+
+    #[inline(always)]
+    pub fn replace<'p: 'h, H: Into<Header<'p>>>(&mut self, header: H) -> bool {
+        let header = header.into();
+        self.headers.insert(header.name, vec![header.value]).is_some()
+    }
+
+    #[inline(always)]
+    pub fn replace_all<'n, 'v: 'h, H>(&mut self, name: H, values: Vec<Cow<'v, str>>)
+        where 'n: 'h, H: Into<Cow<'n, str>>
+    {
+        self.headers.insert(name.into(), values);
+    }
+
+    #[inline(always)]
+    pub fn add<'p: 'h, H: Into<Header<'p>>>(&mut self, header: H) {
+        let header = header.into();
+        self.headers.entry(header.name).or_insert(vec![]).push(header.value);
+    }
+
+    #[inline(always)]
+    pub fn add_all<'n, H>(&mut self, name: H, values: &mut Vec<Cow<'h, str>>)
+        where 'n:'h, H: Into<Cow<'n, str>>
+    {
+        self.headers.entry(name.into()).or_insert(vec![]).append(values)
+    }
+
+    #[inline(always)]
+    pub fn remove(&mut self, name: &str) {
+        self.headers.remove(name);
+    }
+
+    #[inline(always)]
+    pub fn iter<'s>(&'s self) -> impl Iterator<Item=Header<'s>> {
+        self.headers.iter().flat_map(|(key, values)| {
+            values.iter().map(move |val| {
+                Header::new(key.borrow(), val.borrow())
+            })
+        })
+    }
+
+    #[inline(always)]
+    pub fn into_iter<'s>(self)
+            -> impl Iterator<Item=(Cow<'h, str>, Vec<Cow<'h, str>>)> {
+        self.headers.into_iter()
+    }
+}
diff --git a/lib/src/http/mod.rs b/lib/src/http/mod.rs
index 8ba88f6c..85288a4b 100644
--- a/lib/src/http/mod.rs
+++ b/lib/src/http/mod.rs
@@ -17,6 +17,6 @@ mod header;
 pub use self::method::Method;
 pub use self::content_type::ContentType;
 pub use self::status::Status;
-pub use self::header::Header;
+pub use self::header::{Header, HeaderMap};
 
 pub use self::cookies::{Cookie, Cookies};
diff --git a/lib/src/response/named_file.rs b/lib/src/response/named_file.rs
index e3d6b8c6..62ac856c 100644
--- a/lib/src/response/named_file.rs
+++ b/lib/src/response/named_file.rs
@@ -83,7 +83,7 @@ impl<'r> Responder<'r> for NamedFile {
             let ext_string = ext.to_string_lossy().to_lowercase();
             let content_type = ContentType::from_extension(&ext_string);
             if !content_type.is_any() {
-                response.set_header(content_type)
+                response.set_header(content_type);
             }
         }
 
diff --git a/lib/src/response/response.rs b/lib/src/response/response.rs
index 673befb6..41aa8f0a 100644
--- a/lib/src/response/response.rs
+++ b/lib/src/response/response.rs
@@ -1,8 +1,7 @@
 use std::{io, fmt, str};
-use std::borrow::{Borrow, Cow};
-use std::collections::HashMap;
+use std::borrow::Cow;
 
-use http::Header;
+use http::{Header, HeaderMap};
 use http::Status;
 
 pub const DEFAULT_CHUNK_SIZE: u64 = 4096;
@@ -165,7 +164,7 @@ impl<'r> ResponseBuilder<'r> {
 /// Return type of a thing.
 pub struct Response<'r> {
     status: Option<Status>,
-    headers: HashMap<Cow<'r, str>, Vec<Cow<'r, str>>>,
+    headers: HeaderMap<'r>,
     body: Option<Body<Box<io::Read + 'r>>>,
 }
 
@@ -174,7 +173,7 @@ impl<'r> Response<'r> {
     pub fn new() -> Response<'r> {
         Response {
             status: None,
-            headers: HashMap::new(),
+            headers: HeaderMap::new(),
             body: None,
         }
     }
@@ -206,38 +205,30 @@ impl<'r> Response<'r> {
 
     #[inline(always)]
     pub fn headers<'a>(&'a self) -> impl Iterator<Item=Header<'a>> {
-        self.headers.iter().flat_map(|(key, values)| {
-            values.iter().map(move |val| {
-                Header::new(key.borrow(), val.borrow())
-            })
-        })
+        self.headers.iter()
     }
 
     #[inline(always)]
     pub fn get_header_values<'h>(&'h self, name: &str)
             -> impl Iterator<Item=&'h str> {
-        self.headers.get(name).into_iter().flat_map(|values| {
-            values.iter().map(|val| val.borrow())
-        })
+        self.headers.get(name)
     }
 
     #[inline(always)]
-    pub fn set_header<'h: 'r, H: Into<Header<'h>>>(&mut self, header: H) {
-        let header = header.into();
-        self.headers.insert(header.name, vec![header.value]);
+    pub fn set_header<'h: 'r, H: Into<Header<'h>>>(&mut self, header: H) -> bool {
+        self.headers.replace(header)
     }
 
     #[inline(always)]
-    pub fn set_raw_header<'a: 'r, 'b: 'r, N, V>(&mut self, name: N, value: V)
+    pub fn set_raw_header<'a: 'r, 'b: 'r, N, V>(&mut self, name: N, value: V) -> bool
         where N: Into<Cow<'a, str>>, V: Into<Cow<'b, str>>
     {
-        self.set_header(Header::new(name, value));
+        self.set_header(Header::new(name, value))
     }
 
     #[inline(always)]
     pub fn adjoin_header<'h: 'r, H: Into<Header<'h>>>(&mut self, header: H) {
-        let header = header.into();
-        self.headers.entry(header.name).or_insert(vec![]).push(header.value);
+        self.headers.add(header)
     }
 
     #[inline(always)]
@@ -248,7 +239,7 @@ impl<'r> Response<'r> {
     }
 
     #[inline(always)]
-    pub fn remove_header<'h>(&mut self, name: &'h str) {
+    pub fn remove_header(&mut self, name: &str) {
         self.headers.remove(name);
     }
 
@@ -304,7 +295,7 @@ impl<'r> Response<'r> {
         }
 
         for (name, values) in other.headers.into_iter() {
-            self.headers.insert(name, values);
+            self.headers.replace_all(name, values);
         }
     }
 
@@ -321,7 +312,7 @@ impl<'r> Response<'r> {
         }
 
         for (name, mut values) in other.headers.into_iter() {
-            self.headers.entry(name).or_insert(vec![]).append(&mut values)
+            self.headers.add_all(name, &mut values);
         }
     }
 }